Titanium-copper alloy material, and heat-treating or hot-rolling method of titanium-copper alloy

ABSTRACT

Spinodal decomposition of Cu alloy, which contains from 0.5 to less than 5.0% of Ti, is suppressed and a low hardness dispersion of Hv 40 or less is obtained over a sheet surface. In addition, an isotropy in terms of tensile strength in the vertical direction over the sheet surface is improved such that it is 50N/mm 2  or less. In the hot-rolling of the alloy, it is cooled at a cooling speed of not less than 200K (200° C.)/second at least in a temperature range of between 773K (500° C.) and 573K (300° C.).

BACKGROUND OF INVENTION

[0001] 1. Field of Invention

[0002] The present invention relates to a titanium-copper material,which contains not less than 0.5 mass % and less than 5.0 mass % of Ti,the balance being Cu and unavoidable impurities, which is homogeneouslyannealed and cooled so as not to cause spinodal decomposition and hencematerial hardening during the cooling after the solution treatment.

[0003] The present invention also relates to a hot-rolling method and aheat treating method of the titanium-copper alloy, for generating theabove properties.

[0004] Furthermore, the present invention relates to a wroughttitanium-copper alloy having improved homogeneity and bending property,consisting of not less than 0.5 mass % and less than 5.0 mass % of Ti,the balance being Cu and unavoidable impurities.

[0005] The present invention also relates to a method for producingwrought titanium-copper alloy having reduced anisotropy and improvedbending property, by means of subjecting an ingot to rolling, solutionand aging treatments.

[0006] 2. Description of Related Art

[0007] The copper alloy, which contains Ti (hereinafter referred to as“the titanium-copper alloy”) is an aging precipitation type copperalloy. Since the strength and stress-relaxation property are remarkablematerial properties of the titanium-copper alloy, it is broadly used inthe field of electronic parts, terminals and connectors. Thetitanium-copper alloy is melted and cast into an ingot, followed byhot-rolling, cold-rolling, heat-treatment and the like. Surfacetreatment such as plating may be applied on several materials. Theproperties and shape of the titanium-copper alloy material are thusadjusted to the predetermined ones. It is then formed into the parts.

[0008] It is believed that: Ti is contained in titanium-copper alloy asthe super-saturated solid solution; and, the aging hardening occurs whenTi is isolated from the super-saturated solid solution and forms anintermediate Cu₃Ti phase. The titanium-copper alloy is alsocharacterized by higher heat resistance and improved stress relaxationproperty as compared with the high-strength beryllium-copper. Therefore,a blanked and bent sheet and strip of the titanium-copper is broadlyused for electronic parts, terminals and connectors.

[0009] The formability and material properties of the wroughttitanium-copper largely vary depending upon the production conditions,particularly the solution and aging conditions. Spinodal decompositionmay occur depending upon the conditions of the solution treatment. Inthe spinodal decomposition, precipitation from the super-saturated solidsolution occurs without formation of nuclei. When there is fluctuationin the solute concentration of the material, the free energy of thesystem becomes lower than that of the super-saturation solid solution.As a result, phase decomposition proceeds spontaneously without theformation of critical nuclei. In other words, when a small concentrationvariation once occurs in the material, a larger concentration variationis successively induced. Finally, the material is decomposed into twophases. This decomposition occurs abruptly. The spinodal decompositionlargely changes the properties of the material.

[0010] If the spinodal decomposition can be suppressed in thepost-cooling step after the hot-rolling and solution treating steps, notonly is the subsequent working facilitated, but also the dispersion ofmaterial properties is lessened. As a result, the quality is stabilized.The post-cooling condition after the solution-treatment of thetitanium-copper alloy must, therefore, be so adjusted that thedispersion of material properties is lessened and, further, thesubsequent working can be facilitated.

[0011] Furthermore, the anisotropy of the aged titanium-copper alloymust be lessened and the bending property must be improved from theviewpoint of forming the alloy into parts.

[0012] Hardness of the hot-rolled or solution-treated titanium-copperusually lies in the range of Hv 80 to 300 and is largely dependent uponthe composition and cooling speed. Heretofore, when the hot-rolled orsolution-treated titanium-copper alloy is rapidly cooled, since thetemperature and cooling speed vary within the alloy, spinodaldecomposition locally occurs. As a result, the hardness and propertiesso largely vary that the quality and the subsequent working becomeunstable. For example, the hardness dispersion of a strip may amount toHv 100 or more depending upon the heat treating conditions, and in theworst case to approximately ±50% of the average value.

[0013] It seems possible to lessen the hardness dispersion by means ofvarious methods such as {circle over (1)} keeping the finishingtemperature of hot-rolling and the final material temperature after thesolution treatment at a constant level, and {circle over (2)} keepingthe post cooling condition after the hot-rolling and the solutiontreatment at a constant level. It is, however, difficult to completelylessen the hardness dispersion and to attain stable quality by thesemethods, because the spinodal decomposition has the characteristics asdescribed above.

[0014] The conventional rolled titanium-copper material has suchanisotropy that the difference is tensile strength in the parallel andperpendicular directions to the rolling direction amounts to not lessthan 100 N/mm². It has, however, not been elucidated which productionfactor mast significantly influences the anisotropy.

SUMMARY OF INVENTION

[0015] The present invention is based on the recognition of the abovefacts and provides a homogeneous titanium-copper alloy material, thepost forming of which is facilitated.

[0016] The present invention also provides a heat-treating method andhot-rolling method of the titanium-copper alloy, which can suppress thespinodal decomposition and hence the dispersion of properties of thematerial. The quality of the titanium-copper alloy is, therefore,stabilized. The post-aging hardness becomes constant and the postformability is facilitated. As a result, the advantages attained areimprovement of the dimension accuracy of the product, and, further, aproduct having complicated shape can be shaped.

[0017] It was discovered as a result of researches and experiments bythe present inventors that the conditions of solution heat-treatment andthe grain size of the material as solution-treated significantly affectthe properties of the material treated subsequently. The presentinvention is based on this recognition and provides a wroughttitanium-copper material having reduced anisotropy and improved bendingformability required for the manufacturing of parts.

[0018] In accordance with the present invention, there is provided thefollowing material and methods.

[0019] (1) Hot-rolled titanium-copper alloy material havingsolution-treated temper, characterized in that it contains not less than0.5 mass % and less than 5.0 mass % of Ti, the balance being essentiallyCu and unavoidable impurities, and has a hardness difference between themaximum value and the minimum value amounting to Hv 40 or less.

[0020] (2) Hot-rolled titanium-copper alloy material havingsolution-treated temper according to (1), characterized in that it ishot-rolled at a temperature not less than 873K (600° C.) androlling-finished at a temperature not less than 773K (500° C.), followedby cooling at a cooling speed of not less than 200K (200° C.)/second atleast in a temperature range of between 773K (500° C.) and 573K (300°C.).

[0021] (3) Hot-rolled titanium-copper alloy material havingsolution-treated temper, according to (1), characterized in that it issolution-treated by heating at a temperature of not less than 873K (600°C.), followed by cooling at a cooling speed of not less than 200K (200°C.)/second at least in a temperature range of between 773K (500° C.) and573K (300° C.).

[0022] (4) Cold-rolled titanium-copper alloy material havingsolution-treated temper, characterized in that it contains not less than0.5 mass % and less than 5.0 mass % of Ti, the balance being essentiallyCu and unavoidable impurities, and has a hardness difference between themaximum value and the minimum value amounting to Hv 40 or less.

[0023] (5) Cold-rolled titanium-copper alloy material havingsolution-treated temper according to (4), characterized in that it issolution-treated by heating at a temperature of not less than 873K (600°C.), followed by cooling at a cooling speed of not less than 200K (200°C.)/second at least in a temperature range of between 773K (500° C.) and573K (300° C.).

[0024] (6) Titanium-copper alloy material according to (1), (2), (3),(4) or (5) in the form of a sheet, wherein hardness difference of Hv 40or less is satisfied over a sheet surface area of 0.27 m².

[0025] (7) Titanium-copper alloy material according to (6), wherein thehardness is from Hv 80 to 300.

[0026] (8) Titanium-copper alloy material according to (7), wherein thehardness difference is Hv 30 or less.

[0027] (9) Wrought titanium-copper alloy material having improvedbending formability, produced by rolling, solution treatment and aging,characterized in that: it contains not less than 0.5 mass % and lessthan 5.0% of Ti, the balance being essentially Cu and unavoidableimpurities; the grain size is not less than 0.005 mm and less than 0.035mm directly after the final solution-treatment; the tensile strengthunder the wrought state is not less than 800 N/mm²; and the anisotropyin terms of tensile-strength difference between that parallel to therolling direction and perpendicular to the rolling direction is not morethan 50 N/mm², preferably not more than 30N/mm².

[0028] (10) Heat-treating method of titanium-copper alloy, whichcontains not less than 0.5 mass % and less than 5.0% of Ti, the balancebeing essentially Cu and unavoidable impurities, by means ofsolution-treatment and aging, characterized in that it issolution-treated by heating at a temperature of not less than 873K (600°C.), followed by cooling at a cooling speed of not less than 200K (200°C.)/second at least in a temperature range of between 773K (500° C.) and573K (300° C.).

[0029] (11) Heat-treating method of titanium-copper alloy according to(10), wherein the solution-treatment is carried out in an inductionheating apparatus.

[0030] (12) Heat treating method of titanium-copper alloy, whichcontains not less than 0.5 mass % and less than 5.0 mass % of Ti, thebalance being Cu and unavoidable impurities, characterized in that it ishot-rolled at a temperature not less than 873K (600° C.) and finished ata temperature not less than 773K (500° C.), followed by cooling at acooling speed of not less than 200K (200° C.)/second in a temperaturerange of at least between 773K (500° C.) and 573K (300° C.).

BRIEF DESCRIPTION OF DRAWINGS

[0031]FIG. 1 is a graph indicating the relationship between the hardnessof 3.0 mass % Ti—Cu (sheet thickness—0.3 mm) and various startingtemperatures of water cooling (cooling speed—1000° C./sec or more).

[0032]FIG. 2 is a graph indicating the relationship between the hardnessof 3.0 mass % Ti—Cu (sheet thickness—0.3 mm) and the speed of coolingchanged by means of various cooling media, from the starting temperatureof 780° C.

DESCRIPTION OF PREFERRED EMBODIMENTS

[0033] The titanium-copper according to the present invention, containsas the basic components, not less than 0.5 mass % and less than 5.0 mass% of Ti. When the Ti additive content is less than 0.5 mass %,properties such as the strength are poor. On the other hand, when the Tiadditive content is 5.0 mass % or more, the material is excessivelyhardened such that good workability can not be attained. The sameeffects as described hereinabove can also be expected by adding 1.0 mass% or less of Cr, Zr, Ni, Fe and the like. The balance is Cu and theunavoidable impurities.

[0034] The titanium-copper alloy materials (1) and (4) according to thepresent invention has hardness difference between the maximum andminimum values of not more than Hv 40, preferably not more than Hv 30.Taking a sample and measuring the hardness as stipulated under JIS andthe like, the difference between the maximum hardness and minimumhardness is obtained. The titanium-copper alloy material herein is theproduct obtained by the aforementioned method, and its temper state ishot- or cold-rolled and solution-treated. The titanium-copper alloymaterial herein has not yet been subjected to forming as a final productand is, for example, one piece of material, such as one coil, one strip,one wire, one sheet or a lot consisting of cut coil pieces and the likefor the subsequent forming. The hardness dispersion is the differencebetween the maximum and minimum values. The average hardness is, forexample, Hv 190. The hardness dispersion may amount to Hv 60 inconventional material. When this material is cut into pieces forforming, i.e., a work piece, the hardness disperses in a range of fromHv=230−170. It is, therefore, very difficult to obtain flat materialhaving homogeneous formability. Contrary to this, the material accordingto the present invention has considerably reduced dispersion of hardnessattributable to fluctuation in the Ti concentration in thesolution-treated structure. The material according to the presentinvention is, therefore, easy to form.

[0035] The present inventors measured the hardness of a number ofmaterials and discovered that satisfactory homogeneity over the entirematerial is ensured provided that the hardness dispersion over a sheetspecimen of approximately 0.27 m² satisfies Hv≦40.

[0036] A heat-treating method for forming such homogeneous structure isdescribed hereinafter.

[0037] When the heating temperature of titanium-copper is less than 873K(600° C.), since no recrystallization occurs, heat treatment has noeffect to adjust the temper state. The heating temperature is,therefore, not less than 873K (600° C.). When the heating is completed,the cooling is carried out. During the cooling, rapid cooling is carriedout at least in a range of from 773K (500° C.) to 573K (300° C.). Thestarting temperature of rapid cooling is not less than 773K (500° C.)for the following reasons. In the ordinary heat treatment, a continuousplant is used. Various fundamental tests in a continuous plant revealedthat one of the most major reasons for the dispersion of the propertiesis the temperature of the material which is being rapidly cooled, forexample water-cooled, from the heat-treating temperature.

[0038] As is shown in FIG. 1, a critical point is reached atapproximately 863K (590° C.) in the graph indicating the relationshipbetween the hardness and the starting temperature of rapid cooling. Therapid cooling starting at a temperature of not more than 773K (500° C.)cannot impede advancement of the spinodal decomposition and hence localdispersion of the properties. A preferable starting temperature of rapidcooling is not less than 863K (590° C.). After completion of heating thematerial, rapid cooling should, therefore, be carried out as soon aspossible. Since it is difficult by means of a conventional gas-heatingfurnace and electric resistance heating furnace to effectively heat asheet or a strip, while maintaining high productivity, an inductionheating furnace, which enables rapid heating and cooling, should beused. A continuous treatment is carried out to effectively treat thematerial. Material with stable properties can thereby obtained.

[0039] As shown in FIG. 2, there is also a critical point atapproximately 200K (200° C.)/sec in the relationship between the coolingspeed and hardness. The rapid cooling speed is, therefore, not less than200K (200° C.)/sec. The properties of the material are largelyinfluenced by the rapid cooling speed. When the rapid cooling speed isless than 200K (200° C.)/sec, spinodal decomposition takes place and theformability in the subsequent steps is drastically impaired. The coolingspeed is dependent upon the sheet thickness and conveying speed of asheet. The required cooling speed can be fully attained by means ofusing an adequate amount of water. In addition, the rapid cooling iscontinued until the temperature reaches lower than 573K (300° C.),because, if the rapid cooling stops at this temperature or higher,disadvantageously spinodal decomposition occurs during subsequentcooling and the material strength is disadvantageously increased.

[0040] Post-aging tensile strength of less than 800N/mm² isunsatisfactory. When anisotropy in terms of the difference in thetensile strength between the directions parallel and perpendicular tothe rolling direction exceeds 50N/mm², the anisotropy is so serious asto impair the bending formability. The material according to the presentinvention exhibits, therefore, 800N/mm² of the post-aging tensilestrength and 50N/mm² of the anisotropy in terms of the difference in thetensile strength between the directions parallel and perpendicular tothe rolling direction. Such strength and isotropy are not attained inthe conventional material and are attributable to the grain size in theintermediate step, i.e., the grain size directly after the finalsolution treatment. Incidentally, the treatments in the subsequent stepsexert influence upon the intermediate grain size such that the finalgrain size is coarser or finer than the intermediate grain size.However, influence of final grain size upon the anisotropy is slight.

[0041] The grain size of the titanium-copper alloy directly after thefinal solution treatment is not less than 0.005 mm and less than 0.035mm. When the grain size is less than 0.005 mm, the material is locallyuncrystallized and structure control becomes difficult. Furthermore, theinfluence of the preceding working such as cold-rolling remains so thatthe formability of the wrought material becomes unsatisfactory. On theother hand, when the grain size is 0.035 mm or more, the anisotropybecomes so large that the bending formability required in the forming ofparts is seriously impaired.

[0042] The solution treatment is carried out in a continuous heattreatment. In order to obtain the grain size in the range of from 0.005mm to less than 0.035 mm by the continuous heat treatment, theconditions of solution heat treatment are preferably set as follows. Theheating temperature is not less than 923K (650° C.) and less than 1123K(850° C.). The heating time is not less than 10 seconds and less than300 seconds. The speed of subsequent cooling speed is not less than 200K(200° C.)/second. When the heating temperature is less than 923K (650°C.), the grain size mentioned above cannot be obtained even by heatingfor 300 seconds or more. On the other hand, when the heating temperatureis more than 1123K (850° C.), grain growth immediately occurs uponelevation up to this temperature. It is, therefore, difficult to controlthe grain size of the material within the above-described range. Thecooling speed after the solution treatment is not less than 200K/second,because spinodal decomposition occurs and the material is hardened at acooling rate less than 200K/second. Cooling speed of not less than200K/second is attained by means of water-cooling and atomized gas-watercooling. The present invention is hereinafter described with referenceto the examples.

EXAMPLES Example 1

[0043] Titanium-copper alloys, which contain a specified mass % of Tishown in Table 1, were used as the samples. The predetermined componentswere blended and melted in a vacuum melting-furnace to provide thetitanium-copper alloys. The melt was cast into an ingot to provide a 3.5kg ingot (30 mmt×80 mmw×150 mml). The riser portion of the ingot was cutoff and subjected to scalping and milling of the edges in thetransversal direction (10 mm at both edges). The scalped ingot wassoaking-annealed in air at 1123K (850° C.) for 1 hour. Hot rolling wasthen carried out to reduce the thickness from 27 mm to a predeterminedthickness usually 8 mm thickness (8 mmt×70 mmw×562.5 mml). During therolling, the surface temperature of the material was measured by atwo-color type radiation thermometer. When the temperature of thematerial was lowered to a predetermined temperature, water cooling wascarried out. Hardness of the material was then measured (referred to asthe test {circle over (1)}). Cooling speed of the material was adjustedby means of adjusting the thickness of the material and the amount ofcooling water. The cooling speed was preliminarily determined by meansof a thermo couple, which was inserted into the material to obtain thecooling speed under various heat-treating conditions. TABLE 1 Components(mass %) Ti Cu 1 Tinanium-Copper {circle over (1)} 1.5 Balance 2Titanium-Copper {circle over (2)} 3.0 Balance 3 Titanium-Copper {circleover (3)} 4.5 Balance Comparative 4 Titanium-Copper {circle over (4)}0.4 Balance 5 Titanium-Copper {circle over (5)} 6.0 Balance

[0044] The solution treatment was carried out at 1173K (900° C.) for 1hour. The scalping and milling of the edges in the transversal direction(0.5 mm at both edges) were again carried out. Cold rolling was thencarried out to reduce thickness from 7.5 mm to 1.0 mm of thickness (1.0mmt×65 mmw×4210 mml, approximately 0.27 m² of the surface area of asheet). Then, heating was carried out at a predetermined temperature for5 minutes, and cooling was carried out under various cooling conditions,using a Greeble testing device. This method can arbitrarily change theheating and cooling speeds, and can investigate the high-temperatureproperties under a specified heat-treating condition. Hardness onoptional five locations of a rolled sheet was measured. Cold rolling wasthen carried out to reduce the sheet thickness to a predeterminedthickness. Influence of heat-treating conditions upon the properties andformability of the material was evaluated (referred to as the test{circle over (2)}). A contact type thermo-couple was inserted into aheat-treated portion of the material to continuously measure thematerial temperature during the heat-treating. Various cooling speedswere attained by adjusting the amount of water and gas flow rate ofwater cooling, gas-water atomized cooling, and air cooling.

[0045] Table 2 shows the results of the test {circle over (1)}, in whichthe samples were hot-rolled, and cooled under various conditions, andthen subjected to the hardness measurement. A micro Vickers hardnesstester (300 g of load) was used to measure the hardness of optional fivelocations of a sample. The hardness and the difference in hardness wereevaluated. Although the hardness dispersion of Sample Nos. 16 and 17presents no problem at all, since the Ti content is less than 0.5 mass%, the material strength (Hv 200 or more) as the final required propertycannot be obtained after the cold rolling and aging treatment.

[0046] Table 3 shows the results of the test {circle over (2)}. In thistest, 1.0-mm thick cold-rolled sheets were heated at a predeterminedtemperature for 5 minutes, followed by cooling under various coolingconditions. Further working was carried out to reduce the thickness to apredetermined thickness. Occurrence of edge cracks during the coldrolling at 70% of draft was observed to evaluate the cold-rollingworkability of the samples. The cast and heat-treated materialsaccording to the present invention exhibit slight dispersion of theproperties and have improved formability because of low hardness. Thetitanium-copper alloy of stable quality could therefore be produced.TABLE 2 Hardness of Hot-Rolled Copper Alloys Cooled under SpecifiedConditions Cooling Material Starting Starting Spend in Temperature atTemperature Temperature Rapid the End of Hardness (Hv) of Cooling ofRapid Cooling Rapid Cooling Evaluation of (°C.) Cooling (°C.) (°C./sec)(°C.) Material  1 Titanium-Copper 800 700 220 100  80˜100 {circle over(1)}  2 Titanium-Copper 700 650 250 150  90˜110 {circle over (1)}  3Titanium-Copper 800 700 250 100 100˜120 {circle over (2)}  4Titanium-Copper 800 650 250 100 100˜120 {circle over (2)}  5Titanium-Copper 800 600 220 250 105˜135 {circle over (2)}  6Titanium-Copper 750 600 250 100 100˜120 {circle over (2)}  7Titanium-Copper 650 550 250 200 110˜150 {circle over (2)}  8Titanium-Copper 800 600 220 150 115˜145 {circle over (3)}  9Titanium-Copper 750 600 220 100 115˜145 {circle over (3)} 10Titanium-Copper 650 550 220 200 120˜160 {circle over (3)} Comparative 11Titanium-Copper 800 450 220 100 110˜190 {circle over (1)} 12Titanium-Copper 550 500 220 100 130˜230 {circle over (2)} 13 TitaniumCopper 800 450 220 100 130˜230 {circle over (2)} 14 Titanium-Copper 800600 100 100 210˜290 {circle over (2)} 15 Titanium-Copper 800 600 220 400200˜300 {circle over (3)} 16 Titanium-Copper 800 600 220 150  80˜100{circle over (4)} 17 Titanium-Copper 550 500 220 100 140˜160 {circleover (4)} 18 Titanium-Copper Hot-Rolling Cracks Generate {circle over(5)}

[0047] TABLE 3 Hardness of Hot-Rolled Copper Alloys Cooled underSpecified Conditions Material Tempera- Hardness (Hv) of Cooling ture atthe Material & Evaluation Starting Starting Speed in End of ofFormability in Final Temperature Temperature Rapid Rapid Stages ofCooling of Rapid Cooling Cooling Hardness (°C.) Cooling (°C.) (°C./sec)(°C.) (HV) Formability  1 Titanium 750 700 1000   50  80˜100 goodCopper{circle over (1)}  2 Titanium 700 650 800 100  90˜110 goodCopper{circle over (1)}  3 Titanium 800 700 1000  100 110˜130 goodCopper{circle over (2)}  4 Titanium 800 650 1000  100 110˜130 goodCopper{circle over (2)}  5 Titanium 800 600 1000  250  85˜115 goodCopper{circle over (2)}  6 Titanium 750 600 800 100 100˜120 goodCopper{circle over (2)}  7 Titanium 650 550 800 200 100˜140 goodCopper{circle over (2)}  8 Titanium 800 600 800 150 115˜145 goodCopper{circle over (3)}  9 Titanium 750 650 1000  100 115˜445 goodCopper{circle over (3)} 10 Titanium 650 550 800 200 110˜150 goodCopper{circle over (3)} Comparative 11 Titanium 800 450 1000  100110˜190 generation Copper{circle over (1)} of cracks 12 Titanium 550 500100 100 110˜210 generation Copper{circle over (1)} of cracks 13 Titanium800 450 1000  100 150˜210 generation Copper{circle over (2)} of cracks14 Titanium 800 550 100 100 200˜260 generation Copper{circle over (2)}of cracks 15 Titanium 800 600 300 400 2O0˜280 generation Copper{circleover (2)} of cracks 16 Titanium 800 600 220 400 200˜300 generationCopper{circle over (3)} of cracks 17 Titanium 700 450 1000   50 220˜320generation Copper{circle over (3)} of cracks 18 Titanium 800 600 100  50220˜300 generation Copper{circle over (3)} of cracks

Example 2

[0048] A 3.5 kg titanium-copper alloy ingots (30 mmt×120 mmw×100 mml)having the components blended as shown in Table 1 were hot-rolled underthe same process and conditions as in Example 1 to produce an 8-mm thicksheet.

[0049] Although the titanium-copper alloy {circle over (4)} wassubjected to the production process until the final aging, the requiredproperties, i.e., 800 N/mm² or more of tensile strength and 2% or moreof elongation, were not obtained. Cracks were generated during thehot-rolling of the comparative titanium-copper alloy {circle over (5)},the subsequent working of which was therefore impossible.

[0050] The solution-treatment was carried out at 1173K (900° C.) for 1hour. The scalping was then again carried out. The cold-rolling wascarried out to reduce thickness from 7.5 mm to 1.0 mm. Then, the finalsolution-treatment was carried out at a predetermined temperature undervarious conditions using a Greeble testing device, which can optionallychange the heating and cooling speeds. The grain size of the wroughtcopper alloy was then evaluated in accordance with the testing method ofgrain size (JIS H0501). The cold-rolling to reduce the materialthickness to 0.3 mm and then the aging at 673K (400° C.) for 4 hourswere applied to the cold reduced material. A contact type thermo-couplewas inserted into a heat-treated portion of the material to continuouslymeasure the material temperature during the heat-treating condition.Various cooling speeds were attained by adjusting the amount of waterand gas flow rate of water cooling, gas-water atomized cooling, and aircooling. Tensile test specimens were taken from the material in thedirections parallel and perpendicular to the rolling direction toinvestigate the anisotropy. The cyclic bending test was also carried outto investigate the bending property.

[0051] Table 4 shows the conditions of the final heat-treatment. Table 5shows the result of the tensile test and the cyclic bending test. Theaverage value of N=3 was measured in the tensile testing method. In thecyclic bending test, 90° bending around the bending radius of R=0.3 mm(sheet thickness—0.3 mm) was continued until fracture occurred. In Table4, the “fracture” indicates that which occurred at one bending.

[0052] As is apparent from Table 5, the method according to the presentinvention attains the production of copper alloy having reducedanisotropy and improved cyclic bending formability. TABLE 4 Hardness ofHot-Rslled Copper Alloys Cooled under Specified Conditions Cooling SpeedGrain-Size Heating in Rapid after Temperature Heating Cooling Solution K(°C.) Time (sec) (°C./sec) Treatment  1 Titanium 1023(750)  20 1000 10Copper{circle over (1)}  2 Titanium 973(700) 120  800 10 Copper{circleover (1)}  3 Titanium 1073(800) 100 1000 20 Copper{circle over (2)}  4Titanium 1073(800)  15 1000 10 Copper{circle over (2)}  5 Titanium1073(800) 120 1000 30 Copper{circle over (2)}  6 Titanium 1023(750)  30 800 10 Copper{circle over (2)}  7 Titanium 953(680) 250  800 10Copper{circle over (2)}  8 Titanium 1073(800)  60  800 20 Copper{circleover (3)}  9 Titanium 1023(750) 100 1000 20 Copper{circle over (3)} 10Titanium 953(680) 250  800 10 Copper{circle over (3)} 11 Titanium973(700) 200 1000  5 Copper{circle over (2)} Comparative 12 Titanium873(600) 200 1000  5< Copper{circle over (1)} 13 Titanium 893(620) 250 800  5< Copper{circle over (2)} 14 Titanium 1173(900) 120 1000 40Copper{circle over (2)} 15 Titanium 1073(800) 600  800 40 Copper{circleover (3)}

[0053] TABLE 5 Tensile Test and Cyclic Bending Test Grain Size TensileStrength after Heat (N/mm²) 90°Cyclic Bending Treatment Perpen- (Number)(μm) Parallel dicular Parallel Perpendicular  1 Titanium 10 870 890 3 2Copper{circle over (1)}  2 Titanium 10 920 930 3 2 Copper{circle over(1)}  3 Titanium 20 900 910 4 3 Copper{circle over (2)}  4 Titanium 10910 920 3 2 Copper{circle over (2)}  5 Titanium 30 880 900 4 4Copper{circle over (2)}  6 Titanium 10 960 970 3 2 Copper{circle over(2)}  7 Titanium 10 920 940 3 2 Copper{circle over (2)}  8 Titanium 20980 1000  3 2 Copper{circle over (3)}  9 Titanium 20 1000  1030  1 1Copper{circle over (3)} 10 Titanium 10 1050  1070  1 1 Copper{circleover (3)} 11 Titanium  5 1010  1050  1 1 Copper{circle over (2)}Comparative 12 Titanium  5< 930 990 1 Rupture Copper{circle over (1)} 13Titanium  5< 970 1030  1 Rupture Copper{circle over (2)} 14 Titanium 40870 940 2 Rupture Copper{circle over (2)} 15 Titanium 40 950 1020  1Rupture Copper{circle over (3)}

1. Hot-rolled titanium-copper alloy material having solution-treatedtemper, characterized in that it contains not less than 0.5 mass % andless than 5.0 mass % of Ti, the balance being essentially Cu andunavoidable impurities, and has a hardness difference between themaximum value and the minimum value amounting to Hv 40 or less. 2.Hot-rolled titanium-copper alloy material having solution-treatedtemper, according to claim 1, characterized in that it is hot-rolled ata temperature not less than 873K (600° C.) and rolling-finished at atemperature not less than 773K (500° C.), followed by cooling at acooling speed of not less than 200K (200° C.)/second at least in atemperature range of between 773K (500° C.) and 573K (300° C.). 3.Hot-rolled titanium-copper alloy material having solution-treatedtemper, according to claim 1, characterized in that it issolution-treated by heating at a temperature of not less than 873K (600°C.), followed by cooling at a cooling speed of not less than 200K (200°C.)/second at least in a temperature range of between 773K (500° C.) and573K(300° C.).
 4. Cold-rolled titanium-copper alloy material havingsolution-treated temper, characterized in that it contains not less than0.5 mass % and less than 5.0 mass % of Ti, the balance being essentiallyCu and unavoidable impurities, and has a hardness difference between themaximum value and the minimum value amounting to Hv 40 or less. 5.Cold-rolled titanium-copper alloy material having solution-treatedtemper, according to claim 4, characterized in that it issolution-treated by heating at a temperature of not less than 873K (600°C.), followed by cooling at a cooling speed of not less than 200K (200°C.)/second at least in a temperature range of at least between 773K(500° C.) and 573K (500° C.).
 6. Titanium-copper alloy materialaccording to claim 1, 2, 3, 4 or 5 in the form of a sheet, whereinhardness difference of Hv 40 or less is satisfied over a sheet surfacearea of 0.27 m².
 7. Titanium-copper alloy material according to claim 6,wherein the hardness is from Hv 80 to
 300. 8. Titanium-copper alloymaterial according to claim 7, wherein the hardness difference is Hv 30or less.
 9. Wrought titanium-copper alloy material having improvedbending property, produced by rolling, solution-treatment and aging,characterized in that: it contains not less than 0.5 mass % and lessthan 5.0% of Ti, the balance being essentially Cu and unavoidableimpurities; the grain size is not less than 0.005 mm and less than 0.035mm directly after the final solution-treatment; the tensile strengthunder the wrought state is 800 N/mm²; and the anisotropy in terms oftensile-strength difference between that in the parallel andperpendicular directions is not more than 50 N/mm².
 10. Wroughttitanium-copper alloy material having improved formability, according toclaim 9, characterized in that the anisotropy is not more than 30N/mm².11. Heat-treating method of titanium-copper alloy, which contains notless than 0.5 mass % and less than 5.0% of Ti, the balance beingessentially Cu and unavoidable impurities, by means ofsolution-treatment and aging, characterized in that it issolution-treated by heating at a temperature of not less than 873K (600°C.), followed by cooling at a cooling speed of not less than 200K (200°C.)/second at least in a temperature range of between 773K (500° C.) and573K (300° C.).
 12. Heat-treating method of titanium-copper alloyaccording to claim 11, wherein the solution treatment is carried out inan induction heating apparatus.
 13. Heat-treating method oftitanium-copper alloy, which contains not less than 0.5 mass % and lessthan 5.0 mass % of Ti, the balance being Cu and unavoidable impurities,characterized in that it is hot-rolled at a temperature not less than873K (600° C.) and finished at a temperature not less than 773K (500°C.), followed by cooling at a cooling speed of not less than 200K (200°C.)/second at least in a temperature range of at least between 773K(500° C.) and 573K (300° C.).